Easy steps to backup your outlook data files:
1) Close your outlook program
2) select and copy the following texts: Outlook.pst
3) click START and choose SEARCH
4) on the WHAT DO YOU WANT TO SEARCH FOR?, choose ALL FILES & FOLDERS
5) Paste the copied texts in the first search box that says ALL OR PART OF THE FILE NAME and then click search
6) When search is complete, Right-Click OUTLOOK.PST and point your cursor on the SEND TO and then choose your external hard drive or flash-drive (whatever media you have)to start the backup process.